Screw grab



P. YUNGLING scREw .GRAB

Jan. 6, 1931.

Onginal Filed May 29. 1929 2 Sheets-Sheet 1 Jan. 6, 1931. P. YUNGLING 1,787,713

SCREW GRAB original Filed May 29, 1929 2 sheets-sheet 2 INVE/yToR. /Daa/ )//vy//ng BY A TTR NE YS.

Patented Jan. 6, 1931 PAUL YUNeLI'Ne, or vLos"intentes, c'ALIronNiA SCREWGRAB Application ied May ze, leza'seriaiy No. 366303,; Renewed october 22, i930.

This invention relates to lishing tools for use inwell drilling and more particularly tol the type known as grabs. 1n rthe drilling -5 due to mishaps with the drillingtools, or other causes,some`obje ct, 'frequently called a fish, is encountered on the bottomr of' the hole lwhich renders further successful.' ldrilling of the hole impossible, oriat the best difcult. "A grab is one typeof tool developed Y" foi-.removing such objects and is designed to be lowered'into the wellatthe endof av string of tubing, termed the fishing string," and secure the fish and hold it while itis v brought up to the surface of the groundi-- Thepriniary objectof this' invention `1s to provide anr improved type 'ofgrabg` .other objects are, the provision' of agrabinfwhich it is possible, `after getting the initialpho'ld 2o of theiish, to increase the tension of the.` grip by rotating the fishing string;. and one which will not close or operate prematurely.

These objects together with other objects and corresponding accomplishments are se-k cured by means of the embodiment of my invention illustrated in the accompanying drawings,`in which f Fig; 1 is `substantially an axial section through a grab,"as seen; on plane 1-1 of Fig.

3 '5, showing the :jaws in open position; Fig.

2 isal View similar to Fig." 1, showing the jaws closed; Fig. 3 is an elevation as seen looking from the right of F 1, certain parts being broken away to showk details ofl construction;

. Figs. :4, 5, and 6 are views as'seen on the cor,-

respondingly numbered planes of Fig. 1;

Referringwith more particularity to the drawings, 10 denotes the body ofthe grab, preferably cylindrical which is threaded at its uppery end for attachment .to the ishing string A and at its lower end .for the attachment of a skirt 11. It has also an intermediate :threaded portion 12 of reduced d iameter, in which is secured a cage 14 terminating in a' shoulderf 15`at'its upperend, and a bore 16 .formed with a conical seat 17 at itsj lower end. Within this bore and on the seat arefanumber of'slipsl 18 (preferably three) nrged'downwardly by spring 19 andinwardly bythe slope of the seat, into Contact with it'. A number of passages 13 are forn'ied 'in y the body adjacent the bore to permit circulaof deep wells, it frequently,happens that, Y

"skirt -:11 4into thehole. `Three keys 2O are -55` onto pr ss ,from the tubing A out through provided to `cause the shoes to rotate with` form, as ifs:y plainly shown in F igs. 1 and 2Q Er1`he upper surface of the, thread makesan acute angle with the surface vof the stem, while the lower surface makesnearly a right angle.A The inner surface of shoes 18 `is correspondingly threadedj Thus, when force j is exerted tending to movet-he body down- I wardly with respect to the stem, the slips are forced upwardly from their seat against the spring 119 and outwardly by the upper surfface ofthreads, permitting the body and attachedparts tomovedown.v As the points 7U` of thel threads on stem pass those on the slips, the slips are forced back to their originalpo'sition by spring {19,and it the force continues the action repeated. riilrhen the force is reversed so that-.the body tends to move upwardly with respect to the stem, the nearly right angled faces of the threads en- A gage and drag the slips down'the conicall scat, forcing the threads into engagement and preventing furthermovement. In other 801 words, the threads form coacting teeth and a ratchet effect lsjobtained, A small compression spring 23 is mounted in the body in engagement `with each slip to? steady it and urge it against the stem. n To the. upper end Y of stem21 1s threadedly secured a large nut 24, which limits the downward movement of the stem by striking` shoulder 15. The lower end of the stem is iiattened, as best shown in Figs. Zand 1l, and has secured therein two 90 large pins 25, upon which are pivot-ally mounted the jaw members27, these being slotted to receivethe fiat portion of the stem. At the top ofeach jaw :member is a pair oi l pins 29 and'SO, which are connected by ten- 95y sion springs 32 urging the jaw members apart and into contact with skirt 11, the lower end of which is slightly belled.

By referring to Fig". 6, it willbe seen that the backs of the jaws 2"? fit the inside of the Il? skirt 11. They are so curved in a vertical plane as to be forced together or closed as Y tied form may be substituted,y the details ot designV depending on the objectit is 'desired to -the end of a string oit' tubing. i vlowered until bottom is touchcdf'lhe string the skirt moves down and embraces them, (seejFig. 2). The inner surface ofv the jaws may be provided with teeth 28 to prevent the iish slipping from their grip. Jaws of modicatch.

extent by screwing the stein as arout the body as.possible,and the'tool'is attached to is then lowered'a little more which forces the skirt down over the jaws, these resting on thel bottom. This forces them together and any object between'thcm will be gripped.V It a turn or two is now made with the tubing, the

skirt will be further forced over the Vj aws by and-having a downwardly `converging conical seat, a stem disposed within said bore,

f'slips disposed on said seat within' said Vbore and adapted to support said stein,'jaw"mem bersjpivotally attached to said'stem, and a skirt depending Vfrom said body and embracing said jaw members.

2( In a tool of the character described, a body with a bore extending therethrough andjhaving a downwardly converging conical seat the-rein, astem disposed within said bore, a plurality of slips disposed within said bore and urged into contact with'said stem by said seat, aw members'pivotally attached to said stem and a skirt formed on said body andadaptedto closesaid jaws.

' 3. A tool of the character described, conirising a body with a bore extending there-V through, a threaded stem within said bore,

Y correspondingly threaded slips between said bore and said stem, means to urge said slips intoengagement with said stem, )aw members depending from said stem and means' to close said jaw members upon movement of said stem relative to said body.

il. In 'a tool of the character described, a body with a bore extending therethrough and having a downwardly converging conical seat therein, a stem within said bore slips disposed within said bore and about said stem, resilient means urging said slips along said seat and int-o engagement with said stein there being coacting teeth'onsaid slips and said stem whereby one way movement of said stem relative to said slips is permitted, jaws members pivotally attached to said stem resilient means urging said i 1w members apart,

The grab is operated inthe following manner, The jaws are opened -totheirv fnlle st It is Y then and askirt on said body adapted to force said jaw members apart. c

` '5. A tool of the character described comprising a body with a bore extending therethrough, a downwardly converging conical seat in said bore,slips on said seat, means urging said slips downwardly valong said Seat, a stem lwithin said borev normally in threaded engagement with said slips, Jaw Y membersV depending from said stem and pivrotation relative thereto, spring means urgingsaid'slipsdownwardly along said seat, a threaded stem disposedwithin said bore and normally in contact with said slips and supported thereby, jaw members pivotally secured toV said stem, a .skirt on vsaid body adapted to close said jaw members, and spring means adapted to open said jaw members and maintain them in contact withy said skirt.` w Y f V7. A tool of the character described comprising a body having a bore extending therethrough, slips in said bore, a. stem within said bore normally in threaded engagement with said slipsand supported thereby, means to permit disengagement of said rthreads andV upward movement of said stem relative to said slips, jaw members secured to said stem, and a skirt on said body adapted to close said aw members upon upward movement of said stem relativeto said body.

8. A tool of the character described com-A prising abody having a bore extending therethrough, a stem disposed within said bore A and supported by slips therein, aw members secured to said stem and adapted to be closed by askirt on said body upon an upwardmovement ofsaid stem relativeto'said body, means to permit an initial upward movement of said stem without rotation of said body relative to said stem, and means to cause a further upward movement of said stem relative to said body,"upon rotationl ofthe latter relaotally- Secured thereto, a skirt on said body and means urging said )aw members into conday of May, 1929.

teeth on. said yslips and said stem wherebyV one Way movement of said stein relative to said slips is permitted, jaw members pivot- Lally` attached to sald stem, resilient means urging said jaw members apart, and a skirt on said body adapted to force said jaw members together. s A

In vWitness that I Claim the foregoing I have hereunto subscribed my name this 10th PAUL YUNGLING. 

